Identifies which interfaces or networks to include in EIGRP. Interfaces must be configured with addresses that fall within the wildcard mask range of the network statement. A network mask can also be used here.

TIP

The use of a wildcard mask or network mask is optional.

TIP

There is no limit to the number of network statements (that is, network commands) that you can configure on a router.

TIP

If you use the network 172.16.1.0 0.0.0.255 command with a wildcard mask, in this example the command specifies that only interfaces on the 172.16.1.0/24 subnet will participate in EIGRP. However, because EIGRP automatically summarizes routes on the major network boundary by default, the full Class B network of 172.16.0.0 will be advertised.

TIP

If you do not use the optional wildcard mask, the EIGRP process assumes that all directly connected networks that are part of the overall major network will participate in the EIGRP process and that EIGRP will attempt to establish neighbor relationships from each interface that is part of that Class A, B, or C major network.

Router(config-router)#metric weightstos k1 k2 k3 k4 k5

Changes the default k values used in metric calculation.

These are the default values:

tos=0, k1=1, k2=0, k3=1, k4=0, k5=0

NOTE

tos is a reference to the original Interior Gateway Routing Protocol (IGRP) intention to have IGRP perform type-of-service routing. Because this was never adopted into practice, the tos field in this command is always set to zero (0).

NOTE

With default settings in place, the metric of EIGRP is reduced to the slowest bandwidth plus the sum of all the delays of the exit interfaces from the local router to the -destination network.

TIP

For two routers to form a neighbor relationship in EIGRP, the k values must match.

CAUTION

Unless you are very familiar with what is occurring in your network, it is recommended that you do not change the k values.

EIGRP Auto-Summarization

Router(config-router)#auto-summary

Enables auto-summarization for the EIGRP process.

NOTE The behavior of the auto-summary command is disabled by default of Cisco IOS Software Versions 15 and later. Earlier software generally has automatic summarization enabled by default.